1. Field of the Invention
This invention relates to novel organic compounds, and more particularly it relates to novel liquid crystal compounds having a positive dielectric anisotropy, novel organic compounds useful as a component of liquid crystal compositions and liquid crystal compositions containing these novel compounds.
2. Description of the Prior Art
Liquid crystal substances having a positive dielectric anisotropy are not only utilizable for liquid crystal display elements using nematic liquid crystals of a twisted arrangement, i.e. the so-called TN type cells, but also utilized for color liquid crystal display elements having a guest-host effect applied by adding a suitable dyestuff. As for these liquid crystal materials, there is no compound which is singly endurable to practical use in respect of their various performances such as mesomorphic range, operation voltage, response performance, etc. Thus, actually it is the present status that several kinds of liquid crystal compounds or non-liquid crystal compounds are mixed to obtain compositions endurable to practical use.
The object of the present invention is that in a liquid crystal display device wherein a nematic liquid crystal material having a positive dielectric anisotropy is used, a component constituting the nematic liquid crystal material by which the device can be operated under a low threshold voltage and in a small consumption of electric power is provided.
We have made extensive research for compounds satisfying the above object and as a result have found novel compounds having a dicyanopyrazine group.